An AT-cut or other thickness shear crystal vibrator is known as a frequency control element and is used as the reference standard for frequency and time in oscillators in various types of electronic apparatuses.
In such a crystal vibrator, for example as shown in Japanese Patent Publication No. 2008-109538A, a pair of excitation electrodes which face each other in the thickness direction are formed at the center of an AT-cut rectangular crystal blank, and extraction electrodes respectively extracted from this pair of excitation electrodes up to the end parts of the crystal blank are formed.